# Magnetic Field in LC circuit

by bassplayer142
Tags: circuit, field, magnetic
 P: 422 I understand how an LC circuit oscillates and radio waves are a result. I also understand that any light from the electromagnetic spectrum has an electrical and magnetic component. Where does the magnetic component come into play in an LC circuit. Thanks.
 P: 567 An analogy is often discussed: As the voltage across the capacitor increases/decreases, a greater/lesser electric field is formed. As the current through the inductor increases/decreases, a greater/lesser magnetic field is formed.
 P: 422 Does this have to do with self induction?
P: 567

## Magnetic Field in LC circuit

That the voltage across an inductor is proportional to di/dt (and no longer bothering to mention flux when solving circuits), that's what people usually mean when they say self-induction. The way E.E. is usually taught, one day they tell you that the "induction" that you learned about before is more specifically called "self-induction", to contrast with a new topic that's being introduced, called "mutual induction."

You asked what the magnetic field has to do with the oscillation -- in the LC circuit the energy is continuously swapped back and forth between two different forms, between being stored in the electric field and being stored in the magnetic field. This is analogous to some mechanical devices, like the pendulum, or a mass bouncing on a spring, where mechanical energy gets swapped back and forth between kinetic energy and potential energy. Inertia keeps the mechanical gadget going when the potential is at its minimum. Inductance is compared with inertia.
 P: 422 I guess I still don't truly understand. But mostly because this isn't a topic that can be taught on the internet easily without understanding the math. I am going to have to take a class on electromagnetic waves strictly so I guess I will just wait for then. Thanks for the info though.

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